• Adobe After Effects Expressions

  Setting a Mask Name as a variable

  Posted by Ryan Jones on October 3, 2017 at 6:58 pm

  Not sure if this is possible. I have a white solid I’m using as an alpha channel for a painful rotoing job. I have several masks and would like to name them 1-160 (there are 160 frames in this comp) and have the expression say if the timeline is at 50 frames, then Mask 50 will be 100% opacity and zero before and after.

  The manual expression I’m using now is– Mask name is “50” and the opacity of the mask is as follows
  f=50;
  x=timeToFrames(time);
  if (x==f){100}else{0}

  

  I’m trying to avoid changing the value of F for every mask. I’d rather just name it and have F pull the Mask name so I can just duplicate or cut/paste the expression without modifying it. Is this even possible?

  RSJ

  Ryan Jones replied 8 years, 7 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  October 3, 2017 at 7:36 pm

  This should work:

  f=parseInt(thisProperty.propertyGroup(1).name,10);
  x=timeToFrames(time);
  if (x==f) 100 else 0

  Dan
• 

  Ryan Jones

  October 3, 2017 at 7:38 pm

  Well, adding this to my little book of expression shortcuts. Thank you so much!

  RSJ

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